1.) Field of the Invention
The present invention relates generally to cotton cleaning equipment, and, more specifically, to a doffer for a cotton cleaner.
2.) Related Art
Some cotton harvesters, such as the type shown in U.S. Pat. No. 4,606,177 assigned to Deere and Company, include a cotton cleaner for separating seed cotton from trash. The cleaner includes primary and reclaimer saw drums, each having numerous saw tooth discs incrementally spaced along a transverse driven shaft. Seed cotton and trash enter the cleaner and are propelled through a narrow longitudinal opening defined by the outer diameter of the drum, two end walls of the cleaner housing and a lay-down bar. The lay-down bar presses the cotton upon the rotating saw teeth of the primary drum. As the primary drum rotates at high speed, the saw teeth snag the uncleaned cotton and force it through the narrow opening. The snagged cotton is impelled against several radially spaced bars to further enhance the separation of the trash from the seed cotton. The reclaimer drum snags cotton that gets by the primary drum.
A doffer with brushes is rotated at a speed greater than the speed of the primary and reclaimer drums against the tooth discs to dislodge the snagged cotton and propel it towards a conveying duct. The brushes are typically on the order of 1.25 inches (3.2 cm.) tall, and are held by a steel support located behind the brushes. The steel support also acts to dislodge foreign materials such as sticks from the primary drum. Several problems exist with such a brush doffer arrangement. The steel supports often act as a shearing edge that actually cuts off the bristles of the brushes when an obstacle is encountered requiring replacement of the brushes. The brush mounting includes channels secured to cylindrical supports with bolts, and the brushes are attached to the flanges with clamps and additional bolts which extend generally circumferentially through the flanges. These additional bolts are located close to the cylindrical supports and are very difficult to access. Two wrenches must be held close to the saw drums while changing brushes, and there is insufficient space to use a socket with a ratchet or air tool. Therefore, mounting and removing the brushes requires a substantial amount of time and inconvenience. Taller brushes without steel supports are available which do not shear as easily, but without the steel support foreign material often remains stuck to the saws. The clamping bolts for the taller brushes are located even further inwardly than those on the shorter brushes so that access to the bolts for brush replacement is very difficult.
It is therefore an object of the present invention to provide an improved cotton cleaner doffer assembly. It is a further object to provide such a doffer assembly which overcomes most or all of the aforementioned problems and is more efficient and more tolerant to foreign objects entering the cleaner than most previously available assemblies.
It is a further object of the present invention to provide an improved doffer assembly for doffing cotton from a cleaner saw drum. It is a further object to provide such a doffer assembly that is less susceptible to brush damage such as shearing and yet is able to clear foreign matter stuck on the drums.
It is another object of the present invention to provide an improved brush-type doffer assembly having brushes which are easier and faster to attach and remove than those for at least most previously available doffer assemblies. It is another object to provide such an improved assembly having fewer parts and lower cost. It is a further object to provide such an assembly having more easily accessed mountings. It is still another object to provide such an assembly which obviates non-radially extending bolts and the need for two wrenches during brush replacement.
A doffer assembly for doffing cotton from the saw drum of a cotton cleaner includes a plurality of brushes supported by channels and clamps in a drum configuration on cylindrical supports. A first nut on an easily accessible radial retaining bolt holds a doffer channel in position, and a second nut located on the same retaining bolt and tightened against a special clamp secures the brush in place. The special clamp has a first leg positioned over a corner of the channel so the brush is held securely. A second brush-protecting leg extending up in front of the brush removes foreign matter that lodges on the saw drum. The channels which are an integral part of the doffer structure are protected by the clamp for better drum integrity, and therefore there is less opportunity for dirt to collect on the inside of the doffer and cause imbalance in the doffer. The clamp can be easily replaced if damaged. The main structural components are protected by the easily replaced clamps.
The upstanding leg of the clamp protects the brush in the forward direction of doffer rotation. Shear edges behind the brush are eliminated to allow the brush to flex out of the way without damage if a large obstruction is encountered.
The doffer assembly provides better performance and increased tolerance of foreign material on the saw drum. The radial bolt with dual support functions reduces hardware and makes changing brushes easier and quicker than with previously available doffer constructions. A single wrench is all that is necessary for brush changes, and access to the nuts is in an open area away from the saw drum so a socket and ratchet or impact gun can be used for the changes.
These and other objects, features and advantages of the present invention will become apparent to one skilled in the art upon reading the following detailed description in view of the drawings.